Ball and socket articulated or swivel joints have been widely used for many years. These joints can employ a ball and socket with continuous uninterrupted mating or nesting surfaces when only a mechanical capability is sought. However, a conduit or hole is provided in both the ball and socket when it is necessary or desirable to pass a rod, cable or the like through the joint or when the joint is to be used as a fluid swivel through which a fluid is to flow. Ball and socket joints with fluid flow capability across the joint are generally limited as to angular displacement because of the necessity to have the hole in the ball at least in partial fluid flow direct engagement with a similar hole in the socket.
Two present fields greatly interested in ball and socket joints are offshore oil production, processing and transfer, and ship mooring. Offshore buoyant towers supported by the sea floor are used for oil exploration and production and mooring tankers. Such towers are sometimes advantageously secured to the sea floor through an articulated or swivel joint. Ball and socket joints have already been proposed for that purpose. See U.S. Pat. Nos. 4,155,670; 4,058,137; 4,048,944; 3,720,006; 3,708,985; 3,667,239; 3,572,408; and 2,988,144. The prior art, however, does not provide a ball and socket joint with a capability for fluid flow past the joint through a relatively large angular displacement.